TiO_2 对氟金云母微晶玻璃析晶行为的影响

用扫描电镜（ＳＥＭ）、Ｘ射线衍射分析（ＸＲＤ）和差热分析（ＤＴＡ）等方法研究了ＴｉＯ２不同含量的云母微晶玻璃的析晶过程，发现不含ＴｉＯ２的玻璃只发生表面析晶，不能形成云母微晶玻璃。含ＴｉＯ２的玻璃的ＤＴＡ曲线上出现两个玻璃转变温度和两个析晶峰。ＳＥＭ和ＸＲＤ分析表明：云母微晶玻璃的形成决定于晶核剂ＴｉＯ２。ＴｉＯ２使玻璃发生分相，并形成先析钛酸镁晶体，降低了氟金云母的形核势垒。钛酸镁和氟金云母晶体的析晶活化能都随着ＴｉＯ２含量的增加而降低

Effect of TiO 2 on the crystallization of mica glass ceramics

The effect of TiO 2 on the crystallization of mica containing glass ceramics was investigated by differential thermal analysis(DTA), scanning electron microscope(SEM) and X ray diffraction(XRD). Only surface crystallization was observed in the TiO 2 free glass and no mica crystals formed in its crystallization process. Two distinct crystallization exotherm peaks in DTA curves of the TiO 2 containing samples were observed and resolved corresponding to the initial precipitation of MgTi 2O 5, followed by the formation of KMg 3AlSi 3O 10 F 2, confirmed by X ray diffraction analysis(XRD). Two glass transition temperatures also appear on the DTA curves of the TiO 2 containing glasses and phase separation takes place in these glasses when they are heat treated at their nucleation temperatures. By using Kissinger equation, the activation energies for precipitation of MgTi 2O 5 and KMg 3AlSi 3O 10 F 2 crystals were evaluated. Their values decreased with the increase of content of TiO 2.